Log Message:
Update to 4.0.1

Changelog:
from http://owncloud.org/owncloud-4-0-1-release/

Verify if user exists when loggin (oc-863)
More efficient log file handling
PDO requirement check
Check if apps folder is writable
prevent division by zero problem during output of free space
better mysql error message
correctly configure ldap group backend (oc-887)
sort users and groups (oc-779)
LDAP. correctly handle group filter (oc-867)
try to switch magic quotes of globally
fix ategory error reporting (oc-874)
correctly handle reverse proxy / load balancer https handling
prevent session already started warning
fix the files breadcrumb
don¡Çt try to use smtp auth if config files says no
fix versioning path
security: fix a XSS problem in calendar
make LDAP pqsql compatible
fix pqsql database migration
fix ldap config interface
support for LDAP ¡Èmember¡É
don¡Çt hardcode /tmp
fix potential security problem for requested apps parameter
fix notes in contacts properly
fix timezone detection
fix interti_id in calendar
set DB prefix for pqsql
security: fix a XSS problem in contacts
correctly encode caldav link
allow longer path in gallery
disable not compatible apps during upgrade
fix HEAD request for downloads
fix private link sharing via email
use UTC as default timezone
style fixes for tasks app